Currently, a combination of cisplatin and the third-generation antitumor agents (paclitaxel, docetaxel, gemcitabine, vinorelbine or irinotecan), or a combination of carboplatin and paclitaxel is used for standard treatment of advanced non-small-cell lung cancers (Non-patent Documents 1 and 2). However, since these standard treatments merely ensure a response rate of 15.3 to 33.0% and a progression-free survival of four months, the therapeutic effect is not satisfactory.
In addition to those standard treatments, research has been conducted to find combination chemotherapy for non-small-cell lung cancers that can ensure a greater therapeutic effect. For example, a clinical test for a combined use of TS-1 (a combination drug of tegafur/gimeracil/oteracil potassium (mole ratio=1:0.4:1)) and carboplatin was reported. However, the test showed that the response rate of the combined use of these drugs was 33.0%, which is substantially the same as that of the standard treatments (Non-patent Document 3).
As described above, although various combination chemotherapies for treating advanced non-small-cell lung cancer have been intensively developed, the therapeutic efficacies of these treatments are not satisfactory. Therefore, a chemotherapy that ensures further significant therapeutic effects is required.